<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="isCheckAll"/>
    </label>
    <span>
      <span>已完成{{completeSize}}</span> / 全部{{todos.length}}
    </span>
    <button class="btn btn-danger" v-show="completeSize>0" @click="clearCompletedTodos">清除已完成任务</button>
  </div>
</template>

<script lang="ts" setup>
import { computed } from '@vue/reactivity';
import type { Todos } from '../types';

  // props的类型
  interface Props {
    todos: Todos;
    clearCompletedTodos():void;
    checkAll(isCheck: boolean):void
  }

  // 定义接收的props
  const props = defineProps<Props>()

  // 完成数量的计算属性
  const completeSize = computed(() => {
    return props.todos.reduce((pre, todo) => pre + (todo.completed ? 1 : 0), 0)
  })

  // 全选的计算属性(get/set)
  const isCheckAll = computed<boolean>({
    get () {
      return props.todos.length===completeSize.value && completeSize.value>0
    },
    set (value) {
      props.checkAll(value)
    }
  })
</script>

<style scoped>
  .todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }

  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }

  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
  }

  .todo-footer button {
    float: right;
    margin-top: 5px;
  }
</style>
